The purpose of this article is to present a new microstructure which attempts to break away from the traditional predominance of the conceptual dimension of the headword in specialized dictionary entries. Proceeding semasiologically, the microstructure provides not only the conceptual information dictionary users are typically interested in, but also detailed information about the lexico-syntactic characteristics of the relationships holding between terms, particularly compound terms, and the specialized texts that contain them. The article focuses first on the behavioural patterns of terms in discourse and particularly on how terms, and their variants generated by syntactic operations in discourse, augment the overall cohesion of a specialized text. It then introduces the reader to the new microstructure which incorporates information about this particular behavioural pattern.